安全问题已经成为一个越来越重要的问题，在Java中如何对重要数据进行加密解密是本文的主要内容。
一、常用的加密/解密算法
1.Base64
严格来说Base64并不是一种加密/解密算法，而是一种编码方式。Base64不生成密钥，通过Base64编码后的密文就可以直接“翻译”为明文，但是可以通过向明文中添加混淆字符来达到加密的效果。
2.DES
DES是一种基于56位密钥的对称算法，1976年被美国联邦政府的国家标准局确定为联邦资料处理标准（FIPS），随后在国际上广泛流传开来。现在DES已经不是一种安全的加密算法，已被公开破解，现在DES已经被高级加密标准（AES）所代替。
3.3DES
3DES是DES的一种派生算法，主要提升了DES的一些实用所需的安全性。
4.AES
AES是现在对称加密算法中最流行的算法之一。
二、实现所需的一些库
为了实现上述的算法，我们可以实用JDK自带的实现，也可以使用一些开源的第三方库，例如Bouncy Castle（https://www.bouncycastle.org/）和comnons codec（https://commons.apache.org/proper/commons-codec/）。
三、具体实现
1.Base64
1 package com.tancky.security;
2
3
4 import java.io.IOException;
5
6 import sun.misc.BASE64Decoder;
7 import sun.misc.BASE64Encoder;
8
9 public class Base64Demo {
10
11
12 private static String src = "TestBase64";
13
14
15 public static void main(String[] args) {
16 Base64Demo.jdkBase64();
17 Base64Demo.commonsCodecBase64 ();
18 Base64Demo.bouncyCastleBase64 ();
19 }
20
21 //使用JDK的base64实现，
22 public static void jdkBase64 (){
23 BASE64Encoder encoder = new BASE64Encoder();
24 String encode = encoder.encode(Base64Demo.src.getBytes());
25 System.out.println("encode: " + encode);
26
27 BASE64Decoder decoder = new BASE64Decoder();
28 try {
29 String decode = new String ( decoder.decodeBuffer(encode));
30 System.out.println("decode: " + decode);
31 } catch (IOException e) {
32 e.printStackTrace();
33 }
34 }
35
36
37 //使用apache的commonsCodec实现
38 public static void commonsCodecBase64 (){
39 byte[] encodeBytes = org.apache.commons.codec.binary.Base64.encodeBase64(Base64Demo.src.getBytes());
40 String encode = new String (encodeBytes);
41 System.out.println("encode: " + encode);
42
43 byte[] decodeBytes = org.apache.commons.codec.binary.Base64.decodeBase64(encode);
44 String decode = new String(decodeBytes);
45 System.out.println("decode: " + decode);
46
47 }
48
49 //使用bouncyCastlede实现
50 public static void bouncyCastleBase64 () {
51 byte[] encodeBytes = org.bouncycastle.util.encoders.Base64.encode(Base64Demo.src.getBytes()) ;
52 String encode = new String (encodeBytes);
53 System.out.println("encode: " + encode);
54
55 byte[] decodeBytes = org.bouncycastle.util.encoders.Base64.decode(encode);
56 String decode = new String(decodeBytes);
57 System.out.println("decode: " + decode);
58
59 }
60
61 }
2.DES
1 package com.tancky.security;
2
3 import java.security.InvalidKeyException;
4 import java.security.Key;
5 import java.security.NoSuchAlgorithmException;
6 import java.security.NoSuchProviderException;
7 import java.security.Security;
8 import java.security.spec.InvalidKeySpecException;
9
10 import javax.crypto.BadPaddingException;
11 import javax.crypto.Cipher;
12 import javax.crypto.IllegalBlockSizeException;
13 import javax.crypto.KeyGenerator;
14 import javax.crypto.NoSuchPaddingException;
15 import javax.crypto.SecretKey;
16 import javax.crypto.SecretKeyFactory;
17 import javax.crypto.spec.DESKeySpec;
18
19 import org.bouncycastle.jce.provider.BouncyCastleProvider;
20 import org.bouncycastle.util.encoders.Hex;
21
22 public class DESDemo {
23
24 private static String src = "TestDES";
25
26
27 public static void jdkDES () {
28
29 try {
30 //生成密钥Key
31 KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
32 keyGenerator.init(56);
33 SecretKey secretKey = keyGenerator.generateKey();
34 byte[] bytesKey = secretKey.getEncoded();
35
36
37 //KEY转换
38 DESKeySpec deSedeKeySpec = new DESKeySpec(bytesKey);
39 SecretKeyFactory factory = SecretKeyFactory.getInstance("DES");
40 Key convertSecretKey = factory.generateSecret(deSedeKeySpec);
41
42 //加密
43 Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
44 cipher.init(Cipher.ENCRYPT_MODE, convertSecretKey);
45 byte[] encodeResult = cipher.doFinal(DESDemo.src.getBytes());
46 System.out.println("DESEncode :" + Hex.toHexString(encodeResult));
47
48
49 //解密
50 cipher.init(Cipher.DECRYPT_MODE,convertSecretKey);
51 byte[] DecodeResult = cipher.doFinal(encodeResult);
52 System.out.println("DESDncode :" + new String (DecodeResult));
53
54
55
56 } catch (NoSuchAlgorithmException e) {
57 e.printStackTrace();
58 } catch (InvalidKeyException e) {
59 // TODO 自动生成的 catch 块
60 e.printStackTrace();
61 } catch (InvalidKeySpecException e) {
62 // TODO 自动生成的 catch 块
63 e.printStackTrace();
64 } catch (NoSuchPaddingException e) {
65 // TODO 自动生成的 catch 块
66 e.printStackTrace();
67 } catch (IllegalBlockSizeException e) {
68 // TODO 自动生成的 catch 块
69 e.printStackTrace();
70 } catch (BadPaddingException e) {
71 // TODO 自动生成的 catch 块
72 e.printStackTrace();
73 }
74
75 }
76
77
78
79 public static void bcDES (){
80 try {
81
82
83 //使用BouncyCastle 的DES加密
84 Security.addProvider(new BouncyCastleProvider());
85
86
87 //生成密钥Key
88 KeyGenerator keyGenerator = KeyGenerator.getInstance("DES","BC");
89 keyGenerator.init(56);
90 SecretKey secretKey = keyGenerator.generateKey();
91 byte[] bytesKey = secretKey.getEncoded();
92
93
94 //KEY转换
95 DESKeySpec deSedeKeySpec = new DESKeySpec(bytesKey);
96 SecretKeyFactory factory = SecretKeyFactory.getInstance("DES");
97 Key convertSecretKey = factory.generateSecret(deSedeKeySpec);
98
99 //加密
100 Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
101 cipher.init(Cipher.ENCRYPT_MODE, convertSecretKey);
102 byte[] encodeResult = cipher.doFinal(DESDemo.src.getBytes());
103 System.out.println("DESEncode :" + Hex.toHexString(encodeResult));
104
105
106 //解密
107 cipher.init(Cipher.DECRYPT_MODE,convertSecretKey);
108 byte[] DecodeResult = cipher.doFinal(encodeResult);
109 System.out.println("DESDncode :" + new String (DecodeResult));
110
111
112
113 } catch (NoSuchAlgorithmException e) {
114 e.printStackTrace();
115 } catch (InvalidKeyException e) {
116 // TODO 自动生成的 catch 块
117 e.printStackTrace();
118 } catch (InvalidKeySpecException e) {
119 // TODO 自动生成的 catch 块
120 e.printStackTrace();
121 } catch (NoSuchPaddingException e) {
122 // TODO 自动生成的 catch 块
123 e.printStackTrace();
124 } catch (IllegalBlockSizeException e) {
125 // TODO 自动生成的 catch 块
126 e.printStackTrace();
127 } catch (BadPaddingException e) {
128 // TODO 自动生成的 catch 块
129 e.printStackTrace();
130 } catch (NoSuchProviderException e) {
131 // TODO 自动生成的 catch 块
132 e.printStackTrace();
133 }
134 }
135
136
137 public static void main(String[] args) {
138 DESDemo.jdkDES ();
139 DESDemo.bcDES();
140 }
141
142 }
3.3DES
1 package com.tancky.security;
2
3 import java.security.InvalidKeyException;
4 import java.security.Key;
5 import java.security.NoSuchAlgorithmException;
6 import java.security.NoSuchProviderException;
7 import java.security.Security;
8 import java.security.spec.InvalidKeySpecException;
9
10 import javax.crypto.BadPaddingException;
11 import javax.crypto.Cipher;
12 import javax.crypto.IllegalBlockSizeException;
13 import javax.crypto.KeyGenerator;
14 import javax.crypto.NoSuchPaddingException;
15 import javax.crypto.SecretKey;
16 import javax.crypto.SecretKeyFactory;
17
18 import javax.crypto.spec.DESedeKeySpec;
19
20 import org.bouncycastle.jce.provider.BouncyCastleProvider;
21 import org.bouncycastle.util.encoders.Hex;
22
23 public class TripleDESDemo {
24
25 private static String src = "TestTripleDES";
26
27 public static void jdkTripleDES () {
28
29 try {
30 //生成密钥Key
31 KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede");
32 keyGenerator.init(168);
33 SecretKey secretKey = keyGenerator.generateKey();
34 byte[] bytesKey = secretKey.getEncoded();
35
36
37 //KEY转换
38 DESedeKeySpec deSedeKeySpec = new DESedeKeySpec(bytesKey);
39 SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
40 Key convertSecretKey = factory.generateSecret(deSedeKeySpec);
41
42 //加密
43 Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS5Padding");
44 cipher.init(Cipher.ENCRYPT_MODE, convertSecretKey);
45 byte[] encodeResult = cipher.doFinal(TripleDESDemo.src.getBytes());
46 System.out.println("TripleDESEncode :" + Hex.toHexString(encodeResult));
47
48
49 //解密
50 cipher.init(Cipher.DECRYPT_MODE,convertSecretKey);
51 byte[] DecodeResult = cipher.doFinal(encodeResult);
52 System.out.println("TripleDESDncode :" + new String (DecodeResult));
53
54
55
56 } catch (NoSuchAlgorithmException e) {
57 e.printStackTrace();
58 } catch (InvalidKeyException e) {
59 // TODO 自动生成的 catch 块
60 e.printStackTrace();
61 } catch (InvalidKeySpecException e) {
62 // TODO 自动生成的 catch 块
63 e.printStackTrace();
64 } catch (NoSuchPaddingException e) {
65 // TODO 自动生成的 catch 块
66 e.printStackTrace();
67 } catch (IllegalBlockSizeException e) {
68 // TODO 自动生成的 catch 块
69 e.printStackTrace();
70 } catch (BadPaddingException e) {
71 // TODO 自动生成的 catch 块
72 e.printStackTrace();
73 }
74
75 }
76
77
78
79
80 public static void bcTripleDES () {
81
82 try {
83
84 Security.addProvider(new BouncyCastleProvider());
85 //生成密钥Key
86 KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede","BC");
87 keyGenerator.getProvider();
88 keyGenerator.init(168);
89 SecretKey secretKey = keyGenerator.generateKey();
90 byte[] bytesKey = secretKey.getEncoded();
91
92
93 //KEY转换
94 DESedeKeySpec deSedeKeySpec = new DESedeKeySpec(bytesKey);
95 SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
96 Key convertSecretKey = factory.generateSecret(deSedeKeySpec);
97
98 //加密
99 Cipher cipher = Cipher.getInstance("DESede/ECB/PKCS5Padding");
100 cipher.init(Cipher.ENCRYPT_MODE, convertSecretKey);
101 byte[] encodeResult = cipher.doFinal(TripleDESDemo.src.getBytes());
102 System.out.println("TripleDESEncode :" + Hex.toHexString(encodeResult));
103
104
105 //解密
106 cipher.init(Cipher.DECRYPT_MODE,convertSecretKey);
107 byte[] DecodeResult = cipher.doFinal(encodeResult);
108 System.out.println("TripleDESDncode :" + new String (DecodeResult));
109
110
111
112 } catch (NoSuchAlgorithmException e) {
113 e.printStackTrace();
114 } catch (InvalidKeyException e) {
115 // TODO 自动生成的 catch 块
116 e.printStackTrace();
117 } catch (InvalidKeySpecException e) {
118 // TODO 自动生成的 catch 块
119 e.printStackTrace();
120 } catch (NoSuchPaddingException e) {
121 // TODO 自动生成的 catch 块
122 e.printStackTrace();
123 } catch (IllegalBlockSizeException e) {
124 // TODO 自动生成的 catch 块
125 e.printStackTrace();
126 } catch (BadPaddingException e) {
127 // TODO 自动生成的 catch 块
128 e.printStackTrace();
129 } catch (NoSuchProviderException e) {
130 // TODO 自动生成的 catch 块
131 e.printStackTrace();
132 }
133
134 }
135
136
137
138 public static void main(String[] args) {
139 jdkTripleDES ();
140 bcTripleDES ();
141
142 }
143
144 }
4.AES
1 package com.tancky.security;
2
3 import java.security.InvalidKeyException;
4 import java.security.Key;
5 import java.security.NoSuchAlgorithmException;
6 import java.security.NoSuchProviderException;
7 import java.security.SecureRandom;
8 import java.security.Security;
9
10 import javax.crypto.BadPaddingException;
11 import javax.crypto.Cipher;
12 import javax.crypto.IllegalBlockSizeException;
13 import javax.crypto.KeyGenerator;
14 import javax.crypto.NoSuchPaddingException;
15 import javax.crypto.SecretKey;
16 import javax.crypto.spec.SecretKeySpec;
17
18 import org.bouncycastle.jce.provider.BouncyCastleProvider;
19 import org.bouncycastle.util.encoders.Hex;
20
21 public class AESDemo {
22
23 private static String src = "TestAES";
24
25 public static void jdkAES (){
26 try {
27
28
29 //生成Key
30 KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
31 keyGenerator.init(128);
32 //keyGenerator.init(128, new SecureRandom("seedseedseed".getBytes()));
33 //使用上面这种初始化方法可以特定种子来生成密钥，这样加密后的密文是唯一固定的。
34 SecretKey secretKey = keyGenerator.generateKey();
35 byte[] keyBytes = secretKey.getEncoded();
36
37 //Key转换
38 Key key = new SecretKeySpec(keyBytes, "AES");
39
40 //加密
41 Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
42 cipher.init(Cipher.ENCRYPT_MODE, key);
43 byte[] encodeResult = cipher.doFinal(AESDemo.src.getBytes());
44 System.out.println("AESencode : " + Hex.toHexString(encodeResult) );
45
46 //解密
47 cipher.init(Cipher.DECRYPT_MODE, key);
48 byte[] decodeResult = cipher.doFinal(encodeResult);
49 System.out.println("AESdecode : " + new String (decodeResult));
50
51
52
53
54 } catch (NoSuchAlgorithmException e) {
55 // TODO 自动生成的 catch 块
56 e.printStackTrace();
57 } catch (NoSuchPaddingException e) {
58 // TODO 自动生成的 catch 块
59 e.printStackTrace();
60 } catch (InvalidKeyException e) {
61 // TODO 自动生成的 catch 块
62 e.printStackTrace();
63 } catch (IllegalBlockSizeException e) {
64 // TODO 自动生成的 catch 块
65 e.printStackTrace();
66 } catch (BadPaddingException e) {
67 // TODO 自动生成的 catch 块
68 e.printStackTrace();
69 }
70
71 }
72
73
74 public static void bcAES (){
75 try {
76
77 //使用BouncyCastle 的DES加密
78 Security.addProvider(new BouncyCastleProvider());
79
80 //生成Key
81 KeyGenerator keyGenerator = KeyGenerator.getInstance("AES","BC");
82 keyGenerator.getProvider();
83 keyGenerator.init(128);
84 SecretKey secretKey = keyGenerator.generateKey();
85 byte[] keyBytes = secretKey.getEncoded();
86
87 //Key转换
88 Key key = new SecretKeySpec(keyBytes, "AES");
89
90 //加密
91 Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
92 cipher.init(Cipher.ENCRYPT_MODE, key);
93 byte[] encodeResult = cipher.doFinal(AESDemo.src.getBytes());
94 System.out.println("AESencode : " + Hex.toHexString(encodeResult) );
95
96 //解密
97 cipher.init(Cipher.DECRYPT_MODE, key);
98 byte[] decodeResult = cipher.doFinal(encodeResult);
99 System.out.println("AESdecode : " + new String (decodeResult));
100
101
102
103
104 } catch (NoSuchAlgorithmException e) {
105 // TODO 自动生成的 catch 块
106 e.printStackTrace();
107 } catch (NoSuchPaddingException e) {
108 // TODO 自动生成的 catch 块
109 e.printStackTrace();
110 } catch (InvalidKeyException e) {
111 // TODO 自动生成的 catch 块
112 e.printStackTrace();
113 } catch (IllegalBlockSizeException e) {
114 // TODO 自动生成的 catch 块
115 e.printStackTrace();
116 } catch (BadPaddingException e) {
117 // TODO 自动生成的 catch 块
118 e.printStackTrace();
119 } catch (NoSuchProviderException e) {
120 // TODO 自动生成的 catch 块
121 e.printStackTrace();
122 }
123
124 }
125
126
127 public static void main(String[] args) {
128 jdkAES();
129 bcAES();
130
131 }
132
133 }